The present invention relates to an ink container for storing ink, and an ink jet cartridge comprising such an ink container.
In some cases, an ink container for supplying ink to the recording head of an ink jet recording apparatus is placed apart from the recording head so that the level of the ink within the ink container is differentiated from the level of the recording head in order to use head pressure difference to provide the recording head with a stable supply of ink. In these cases, there is a possibility that if the balance in head pressure is disturbed, ink might leak from the recording head, and/or the recording head might be supplied with an insufficient amount of ink, which might result in the deterioration of recording performance.
In other cases, an ink container is mounted on a carriage along with a recording head, and an ink retaining member, which retains ink by generating a predetermined amount of ink retaining force, is placed within the ink container. More specifically, a porous ink absorbing member, as an ink retaining member, is placed within the ink container to cause the ink absorbing member to absorb and retain ink so that negative pressure is generated in the ink container by the capillarity in the ink absorbing member. Thus, unless the properties of the ink absorbing member as a negative pressure generation source are optimized for negative pressure generation, ink might leak from the recording head and/or recording performance might deteriorate due to the insufficient supply of ink to the recording head.
In the cases of the above described ink delivery structures, the internal pressure of an ink container tends to be affected by the changes in the environmental factors, for example, ambient temperature, atmospheric pressure, vibration, and the like. It also tends to be affected by the manner in which the recording head is driven, because the manner in which recording head is driven affects the amount of ink supplied to the recording head. Further, there is a possibility that as the internal pressure of an ink container changes, the ink retaining member such as the aforementioned ink absorbing member might fail to properly retain the ink within the ink container.
One of the proposals for improving the above described structures is disclosed in U.S. Pat. No. 5,500,663, according to which ink supplying performance is improved by providing an ink container with a single or plurality of sub-structures for regulating the internal pressure of the main structure of the ink container.
The addition of a pressure regulating means made it possible to stably supply ink, and also to suppress the fluctuation of the internal pressure of an ink container for which changes in the environment of the ink container are responsible.
However, the addition of a pressure regulating means alone was not sufficient to completely solve the problems, since an ink container such as the above described one was structured so as to be removably connected to an ink jet recording head such as the above described one. In other words, there was much to be improved regarding the juncture between the ink container and recording head in terms of stability and reliability.
Regarding the structure of the junction, there have been many proposals, according to which the ink delivering portion of an ink container is provided with a valving structure. However, those proposals leave much to be improved. That is, the provision of a valving structure increases component count, which results in such problems as structural complication and cost increase. In other words, those proposals are problematic in that they fail to provide an inexpensive ink container.
Accordingly, the principal object of the present invention is to provide an ink container capable of always properly retaining ink within the main structure of the ink container in order to stably supply ink even if changes occur to the environment of the ink container, by providing the ink delivering portion (connecting portion) of the ink container with a valving structure which is simple and reliable, and also to provide an ink jet cartridge comprising such an ink container.
According to an aspect of the present invention, there is provided an ink container for supplying ink out of a main body thereof through an ink supply port, said container comprising an ink retaining material for retaining the ink in the main body of the container; pressure adjusting means for adjusting a pressure in the main body; and a valve member disposed in the ink supply port; said valve including a substantially non-elastic plug member for plugging said ink supply port and an elastic member for urging said substantially non-elastic member toward said ink supply port.
According to another aspect of the present invention, there is provided an ink cartridge comprising an ink container as defined above; an ink jet recording head capable of ejecting the ink supplied through said ink supply port of said ink container.
These and other objects, features, and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings.